The invention discloses an efficient wall-penetrating-type fresh air purifying device, and belongs to the technical field of fresh air purifying. The efficient wall-penetrating-type fresh air purifying device comprises an indoor face plate, a wall penetrating body, an inner barrel, an outer barrel and an outdoor air-inlet rain cover. The outer barrel is in sliding fit with the inner barrel, and the outer side of the outer barrel is in close fit with the inner wall of a wall hole. An HEPA filter, a low efficiency filter and a full-plastic-packaging axial flow fan are arranged in the wall penetrating body. The HEPA filter is an HEPA folded conical core filter. The HEPA folded conical core filter comprises an HEPA folded filtering conical core, a top positioning disc and a bottom air stopping disc. The HEPA folded filtering conical core is connected with the bottom air stopping disc through hot melt adhesive and connected with the top positioning disc through hot melt adhesive. The diameter of the top of the HEPA folded filtering conical core ranges from 100 mm to 500 mm, the diameter of the bottom of the HEPA folded filtering conical core ranges from 30 mm to 400 mm, and the height of the HEPA folded filtering conical core ranges from 100 mm to 300 mm. A circular air hole is formed in the middle of the top positioning disc, and the diameter of the circular air hole ranges from 70 mm to 470 mm. The efficient wall-penetrating-type fresh air purifying device has the beneficial effects of being low in density, small in air resistance, large in air volume, long in service life, low in cost and ideal in dust removal effect.